High-precision and high-definition real-time ranging is desired in automatic driving, gesture identification, machine vision and the like fields. Therefore, laser radars and 3D imaging technologies based on time of flight (TOF) of photons are being more and more widely applied.
The laser radars and 3D imaging technologies based on the TOF are composed of a transmitter end and a receiver end. The transmitter end generates pulse-modulated laser signals, and the receiver end detects optical signals reflected from a target object, and calculates a distance to the target object by the TOF of photons. Detection of the distance is mainly subject to a power of the transmitter end and a sensitivity of the receiver end. For implementation of the ranging function, the transmitter end needs to output laser pulses having a controllable and stable power.
During practice of the present application, the inventors have identified that a circuit of the transmitter end and a driven laser device are both sensitive to temperature variations, process deviations, and power source voltages deviations (referred to as PVT variations). These factors may cause deviations of the power of the output laser. These three factors are mainly introduced from the following three aspects. First, during operating of the transmitter end, the temperature may vary at the entire transmitter end due to time and variations of ambient temperature. Second, the laser device and the interior circuit of the transmitter end may be subjected to some process deviations during fabrication. Third, the supplied voltage at the transmitter end may also be deviated. These three major factors may cause the power of the output laser to be deviated from a predefined value, such that the laser radar and 3D sensor may fail to implement the ranging function.